Re: 12 LED resistance circuit help

On Mon, 25 Apr 2005 20:11:58 GMT, "Anthony Fremont"
<spam@xxxxxxxxxxxx> wrote:

>
>"John Fields" <jfields@xxxxxxxxxxxxxxxxxxxxx> wrote in message
>news:fe8q61pdi7787n4c5c2sqvsqhj77nb9vrf@xxxxxxxxxx
>> On Mon, 25 Apr 2005 00:43:35 GMT, "Anthony Fremont"
>> <spam@xxxxxxxxxxxx> wrote:
>>
>> >
>> >"John Fields" <jfields@xxxxxxxxxxxxxxxxxxxxx> wrote in message
>> >
>> ><snipped a bunch more side-stepping and invective/ad-hominem crap>
>>
>> ---
>> Translation: "The sonofabitch nailed me, so I'll just shout one more
>> insult and pretend he didn't. And now for something completely
>> different..."
>
>However you wish to see it John, though I didn't use any cuss words.

---
'Crap" is a cuss word, and besides, "The thought is the same as the
deed."
---


>> >> ---
>> >> HC4066, about 50 cents, cap about a dime, resistors about a nickle,
>> >> diodes about a nickle so, for a one off, that's about $0.70.
>> >
>> >Didn't you have a pot in your design?
>>
>> ---
>> Yeah, but it was a nicety. For the cost-conscious, and if the period
>> isn't all that critical, 510k +/- 5% will be just fine.
>
>I'd go with jumpers on a micro. They're cheap and highly configurable.

---
Not as configurable as a delta R, and good luch with those jumpers on
an 8 pin chip.
---

>
>> >> PCB, transistor, relay is a wash for either system.
>> >
>> >Probably wouldn't need a transistor to drive the relay as long as
>> >5V@25mA will do it. Why not a nice SSR instead?
>>
>> ---
>> Oh, I don't know... Maybe because that's not what the OP of the thread
>> in sed you referenced asked for?
>
>An SSR doesn't qualify as a relay?

---
Not as a relay with mechanical contacts, but it doesn't matter. The OP
asked for something which could _drive_ a relay, which is what I gave
him. I showed a mechanical relay because that's what he said he was
going to use, but if he wanted to switch to an SSR, that would be up
to him.
---


>> >> A one off for a micro is gonna cost you the micro, a programmer, a
>> >> learning curve and programming and debugging time.
>> >
>> >How come the full cost of a programmer and the micro's entire
>learning
>> >curve gets factored in every time a micro is mentioned as a solution?
>>
>> ---
>> Because if you haven't bought/built one and you haven't been through
>> the process, then you'll have to buy/build one and go through the
>> process if you want to play.
>> ---
>
>The same goes for test equipment, soldering stuff etc.... It's just one
>more tool that you need, nothing more. A good PIC programmer is less
>than $100. Compared to the $150 I spent on my audio frequency generator
>that I almost never use, it's a great investment.
>
>> >It's a one time cost, just like the rest of anyones test equipment or
>> >education.
>>
>> ---
>> Yes, of course, but it's a one-time cost and an ongoing effort which
>> will will be unwarranted if the goal at hand is to build a one-off
>> widget with a total cost of, say, $10 or less.
>
>But it would be worth buying a DMM, a soldering iron, solder, etching
>stuff etc.....?

---
You'd need that stuff whichever way you decided to go, but you'd only
need the other stuff if you were going to implement the device using a
micro, so it would be stupid to go that way when the other way is so
simple.
---

>> >I spent less than $75.00 on my programming hardware and the
>> >dev tools were free from Microchip. My scope cost me more than $400
>> >fifteen years ago and it was used then. Nobody worries about the
>> >thousands of dollars needed for the rest of the stuff you need to
>> >effectively tinker in electronics, just the $50 for the programmer
>like
>> >it's some kind of major show-stopper.
>>
>> ---
>> The keyword there is 'tinker'. If that's _your_ bent, then fine.
>> Spend away. Understand however, that that's not _everyone's_ cup of
>> tea and that some folks only want a simple, inexpensive, easily
>> realizable solution for a problem peculiar to them. Asking them to
>
>Well, I guess that I see PIC chips like you see 74xx's

---
I doubt it. I work in both camps as well as in analog, and so far
you've demonstrated no skill with anything other than some alluded-to
ability to substitute programming for hardware you admittedly don't
understand and don't want to "take a lifetime to learn", or something
like that.
---

>
>> spend _anything_ on hardware which is going to gather dust after the
>> project is finished is, at best, stupid. As is asking them to spend
>> time learning how to use it, and to acquire the software skills
>> necessary to bring the "project" to completion.
>
>Burning yet another straw man, you really are a fire bug. I don't
>recall asking anyone to spend money on equipement to be used once.

---
It's not a straw man at all.
When you insist that using a µC is a better solution than using
"discrete" logic, then if that insistance bears fruit, the requirement
for the equipment necessary to implement your solution will become
de rigueur. If the breadth of the project is the yield of a single
unit with a cost basically down in the noise compared to the required
expenditure in time and money to complete the project, then doesn't it
seem stupid to you to do it that way when doing it in hardware would
be so much faster and less expensive?
---

> As I "self agrandised" before, if I was adamently suggesting a PIC to
>someone, I'd be offering some help to go with it. You can make of that
>what you wish.

---
>From what you've offered so far, I would suggest that anyone who
decides to go that route find help elsewhere.
---

>> >IME, debugging time for this
>> >project would be virtually non-existent and the end result would be
>more
>> >useful since it would have a much greater dynamic range on the time
>> >constant.
>>
>> ---
>> If you think the OP was wrong in asking for what he wanted, then why
>> don't you get your ass over to sed and tell him about it instead of
>> sitting here playing self - aggrandising games and kvetching about
>> every goddam thing under the sun?
>
>Er um, because I don't want to. You really ought to stop trying to
>control things around here. Ordering people around on usenet is not
>likely to win you many friends.

---
Er um, because you're a chicken*** and you know that if you do you're
going to wind up getting your ass handed to you. Again.
You really ought to follow your own advice, hypocrite. You telling me
to stop trying to control things around here is you trying to control
me. Friends I've got. Insignificant gadflies like you I don't need.
---

>> Hint: He doesn't _want_ to be able to change the timing, he just
>> wants something that'll give him a contact closure, repeatedly, every
>> hour or so.
>> ---
>>
>> >> You figure it out.
>> >
>> >Your cost may be a little less assuming a PIC 12Fxxx (~1.20 single
>qty),
>> >but a 4 bit micro would change that.
>>
>> ---
>> YAFI, LOL! Suggest away, and don't forget to include the cost of the
>> programmer and the dev tools, and the time required to learn how to
>> use them and to learn the instruction set.
>
>Programmers and dev tools don't count. We've already covered this.
>They are in the same category as all other dev tools and electronics
>equipment you own.

---
Other than your just being obstinate, I fail to see why, (without
even going into the learning curve part of it) you think that paying
money for dev tools which will only be used once is better than not
having to pay for the dev tools, yet winding up with exactly what you
want anyway.
---


>> >Outside of the minor cost
>> >difference, I still feel that the micro offers far more potential for
>a
>> >better end result.
>>
>> ---
>> "Minor cost difference"? You're either trying to sneak some *** in
>> there or you can't do, or haven't done, the arithmetic, so I'll do it
>> for you: Since the transistor, the base resistor, the clamp diode,
>> the relay and the PCB are a wash, what's left is $1.20 for your
>> suggested PIC way VS about $0.63 for my way.
>>
>> That comes to:
>>
>>
>> $1.20
>> -$0.63
>> ------
>> $0.57
>>
>> which is about 1/2 as expensive as your way. "Minor cost difference"?
>> I think not.
>
>It's certainly not half as expensive when you factor in a board and the
>rest of the common parts. The difference quickly shrinks to ~10% or
>less, now doesn't it?

---
That's a good point but, bottom line, you still save about 50 cents if
you don't do it with a micro and you don't have to learn how to do it
and buy all the stuff to do it with if you're not going to do it
again.
---
>
>> Hmmm... Where did I read this:
>>
>> "BTW, I feel that a microcontroller would be a simpler, cheaper, more
>> reliable (iow better) solution to the problem of resetting the network
>> appliances on a regular basis. What do you think?"
>>
>> 1. Cheaper? I've just proven that it's not cheaper in onesies, and I
>> doubt that with that huge cost differential it could be made cheaper
>> in volume.
>
>Admittedly for one off, it's pretty hard to be cheaper using an 8-bit
>micro. A 4-bit proc would do the job, and it would be cheaper. BTW,
>your quoted prices were a bit low as shown on Digikey, so things aren't
>as bad as you wish to make it seem. Of course your price was 70 cents
>yesterday and now it's only 63 cents, so why am I not surprised?

---
Because you're stupid?
---

>According to Digikey, the fairchild 4060 is 77 cents in single qty, the
>ST part is 55 cents each.
>
>> 2. Simpler? Since the µC way would require a large investment in time
>> in order to climb the learning curve, that can hardly be considered a
>> simpler solution for a one-off.
>
>What about the electronics learing curve? It's only about 1000 times
>larger, be for real. That's the same old tired mantra formerly sung by
>"professional tube circuit designers" when whining about having to learn
>yucky old transistor theory.

---
Dumbass, the OP over on SED wasn't interested in spending a great deal
of time and some bucks on learning how to design a µC timer; what he
wanted was something quick and easy which he could solder up, probably
on a piece of perfboard, which would do what he wanted. That's what
he got, and I got private email from him thanking me for the circuit
and letting me know that he'd let me know how it worked out. Rest
assured that I'll post the good news when I hear it.

Now, do you have any comments on whether it'll work or not? Why don't
you build one and find out? It'll only cost you five bucks or so and
we'll learn whether you know how to solder or not. Or wire-wrap. Or
whether you're just plain ol' fulla ***.

--
John Fields
Professional Circuit Designer
.

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